The revised certification is needed because the current regulations have been found to be inadequate. American manufacturer Navistar was among their first to signal that some vehicles which operate in the absence of liquid urea are capable of meeting federal NOx emission regulations, although they spit out 10 times more NOx then they would have in the presence of urea.
“Navistar first identified these loopholes to the agencies and also presented our concerns at today’s workshop,” Jack Allen, Navistar North American truck group president said when presenting the company's findings to the EPA and CARB. “We will be working with the EPA and CARB to ensure full environmental compliance.”
A research conducted by environmental consulting firm EnSIGHT found that in the absence of urea (a liquid used to clean up NOx emissions), the vehicles’ operations were not affected. The SCR system was even tricked to run on water instead of urea and even with no liquid at all. Needless to say, although meeting federal regulations, the NOx emission levels increased as a result of the lack of urea.
“Truck owners are paying a substantial price to comply with 2010 NOx requirements,” Allen added. “They, and the public, deserve to know that the new equipment they are purchasing actually works as promised to curb pollution. It’s obvious, however, that these trucks can operate effectively without liquid urea, and that under these and other conditions, SCR NOx emission control is turned off."
"We’re calling on the EPA and CARB to assure that all vehicles, not just ours, work when they are supposed to be working.”